Pyrotechnic disseminating formulation

ABSTRACT

This invention comprises a pyrotechnic disseminating composition employing an aminosubstituted thiourea compound as a fuel, an inorganic oxidizer, such as alkali metal and ammonium chlorates and perchlorates, which readily is combustible at atmospheric pressures as oxidizer and effective quantities of an agent to be disseminated.

Unlted States Patent 1 1 1 1 3,929,530

Niles Dec. 30, 1975 [54] PYROTECHNIC DISSEMINATING 2,557,815 6/1951 Wheelwright et al 149/83 x FORMULATION 2,637,678 5/l953 Peer et al [67/40 [75] Inventor: Earl Thomas Niles, Midland, Mich.

Primary Examiner-Benjamm R. Padgett [73] Assrgnee: The Dow Chemical Company, Assistant Miner Mldland, Attorney, Agent, or Firm-C. Kenneth Bjork; Lloyd S. 22 Filed: Nov. 21, 1966 lowanovitl [2]] Appl. No.: 596,008

[57] ABSTRACT This invention comprises a pyrotechnic disseminating 149/1092 composition employing an aminosubstituted thiourea [51] Int. Cl. C06D 3/00 Compound as a fuel, an inorganic oxidizer, such as all l Fleld of Search kali metal and ammonium chlorates and perchlorates, 167/40 which readily is combustible at atmospheric pressures as oxidizer and effective quantities of an agent to be References Cited disseminated UNITED STATES PATENTS 6/1951 Dinsdale et al. 149/83 X 6 Claims, N0 Drawings PYROTECHNIC DISSEMINATING FORMULATION This invention relates to pyrotechnic dissemination and more particularly is concerned with disseminating systems based on novel pyrotechnic fuel formulations employing aminosubstituted thioureas as a fuel.

Pyrotechnic disseminating formulations are widely employed for colored smoke production used as a signal or screen, for the distribution of plant growth regulating agents such as pesticides, fumigants, herbicides and the like and for the release and distribution of chemicals used in warfare and law enforcement such as tear gas, psychotomimetic incapacitating agents and the like.

The primary problem in disseminating such signalling and treating materials, hereinafter referred to as agents, by pyrotechnic means is in providing a combustible mixture evolving large quantities of gaseous combustion products which burns at a sufficiently low temperature such that the agent being disseminated is not detrimentally degraded or destroyed. In general, such compositions should provide large volumes of gaseous combustion products while undergoing complete burning at a low burning pressure, eg a maximum of about two atmospheres, and a maximum burning temperature of about 800 C. and preferably from about 300 to about 600 C. It is another criterium of operation that the agent to be disseminated must be compatible with the pyrotechnic composition to assure reliability of burning after storage as well as storageability without mix degradation.

Heretofore, pyrotechnic dissemination of smoke dyes, herbicides, chemical warfare materials, tear gas and other like agents has been carried out using compositions wherein substantial amounts of the agent to be disseminated are mixed with cool burning fueloxidizer combinationss which provide copious quantities of water vapor and carbon dioxide as the principal gaseous exhaust products. In these formulations, many times undesirable high percentages of the agent are lost through'degradation during the combustion dissemination process.

Empirically, it has been found that a mixture of carbohydrates or sulfur with potassium chlorate in the presence of minor amounts of certain additives, e.g. sodium bicarbonate with sulfur or kaolin with sugar, can be used as a pyrotechnic system for dissemination of colored smoke and chemical warfare agents. These systems can be classified as cool-burning" only because of the flame quenching additives employed therein. Polyvinyl acetate in dilute solutions has been used with these conventional pyrotechnic compositions to increase their physical strength and ease of consolidation. Such solutions reduce the amount of pressure needed to compact the formulations into a grain. This is of interest especially with those formulations containing sulfur as compaction of such formulations at high pressure is hazardous in that these compositions during fabrication are prone to ignition. Even when partially compacted, the deflagration borders on detonation with respect to velocity. Oil, as a diluent, has been used to moisten and reduce friction sensitivity in such mixtures. This material, however, undesirably degrades the composition from the standpoint of efficiency of dissemination. Thiourea also has been used as a fuel in such compositions. However, it has not proved to be satisfactory since it shows instability in organic dye systems and has not been found to be compatible with certain chemical warfare agents. Additionally, with some agents, mixes containing thiourea have been found to be very impact sensitive even to the point where these could be dangerous to process and store.

Dissemination of agents of the type set forth herein also has been realized using pyrochemical gas producers as the high volume gas source. To illustrate, selfsustained gas producing reactions as realized by the relatively low temperature catalytic decomposition of ammonium nitrate, guanidine nitrate and nitroguanidine utilizing chromates and dichromates as catalysts have been used to disperse benzene hexachloride, DDT and other pesticides. These formulations suffer from the disadvantage that they exhibit relatively low efficiency of dissemination and are not universally applicable.

It it a principal object of the present invention to provide a novel pyrotechnic composition for dissemination of smoke dyes, pesticides, chemical warfare and the like agents.

It is also an object of the present invention to provide a pyrotechnic formulation which is safe to handle during mixing and other production operations when in admixture with an agent to be disseminated.

It is a further object of the present invention to provide a pyrotechnic formulation containing an agent to be disseminated wherein the resultant composition remains stable under prolonged storage even at relatively elevated temperatures of 60 C. or more and which gives high efficiencies of gaseous combustion production and agent dissemination upon use.

It is another object of the present invention to provide a pyrotechnic composition suitable for use with a wide variety of agents ordinarily dispersed by pyrotechnic dissemination.

It is also an object of the present invention to provide a cool-burning pyrotechnic composition for dissemination of agents which requires no coolant additives.

These and other objects and advantages readily will become apparent from the detailed description of the invention presented hereinafter.

The present invention comprises a pyrotechnic disseminating composition employing an aminosubstituted thiourea compound as a fuel, inorganic oxidizers which readily are combustible at atmospheric pressures as oxidizer and effective quantities of an agent to be disseminated.

More particularly, the present invention comprises from about 6 to about 23 weight per cent of thiosemicarbazide,

i H NNHiiLNH (hereinafter designated as TSC), ethylenebis(thiosemicarbazide),

(coded as EBS), thiocarbohydrazide,

s ll nmuncunun (herein designated as TCH) and dithiobiurea,

4 homogeneous mix into a container, compacting the mix in the container and contacting the so-compacted formulation with an ignition system and igniter.

Internal burning grains are prepared by pressing or 5 compacting the blend around a mandrel of predetermined shape and size. 5: i The present novel pyrotechnic disseminating formu- H N NHNH NH lation offers the unex ected advanta es of safet dura I q p g y mg mixing with agents that are somewhat hazardous to (denoted as DTB), from about 20 to about 36 weight handle in the presence of sulfur. Also, they provide per cent of an alkali metal or ammonium chlorate or P hlgh stjablhty din-mg Storage as perchlorate such as, for example, sodium chlorate (Nahlgher etlficlency of dlssemmano. when compareid with C103), potassium chlorate (K003) or ammonium Pep formulations based on conventional pyrotechnic syschlorate (NH ClO and balance agent to be dissemitems' nated. A preferred embodiment of the present inven- The followmg .EXamPles serve to further. i tion Comprises from about 8 to about 13 weight per trate the present invention but are not meant to limit it cent of a fuel as listed directly hereinbefore, from about thereto 23 to about 30 weight per cent potassium chlorate, and EXAMPLE 1 balance agent to be disseminated. l l l b f f 1 These formulations exhibit a satisfactory burning For aeroso eva uanon a .arge E g olrmu rate, are cool burning and develop copious quantities Hons were prepared by.mlxmg a an yst (I of neutral (i.e. substantially non-reactive with agent) catalyst was employed?,mcorporatmg agemmto gaseous combustion products to provide good agent system followed by oxidizer. The resulting formulat on dissemination. If desired, however, optionally up to 25 totanmg l0 t was mlxeld remotely m a g z about 10 per cent by weight, preferably from about 0.2 bottle to provlde a Substantially hpmqgeneous to about 2 weight per cent of a Combustion catalyst The so-blended pyrotechnic disseminat ng composition e g chromates copper salts platinum rhodium was placed in a small metal can (1.125 mches diameter 1 a a iridium metals, ferrocene,metal chromites, ferric oxide by g i g g conpacmd by if l i and the like can be incorporated into the formulation. pressure 0 a out Penn 8 per sguare mc g Alkali metal chromates, e.g. potassium chromate of the can was plerced toprovlde an me (K CrO,,) and copper halides, e.g. copper chloride, g lg g' MIL E i If: Fire l s; have been found to be particularly suitable catalysts. lgmtgr vlvas :l 5 dissrsmignation The use of the combustion catalyst appears to stabilize g f p ace m con ac e the burning rate somewhat and provide more consisf a d and burnin charactep tent results particularly with the faster burning compop gram i g b sitions. This in turn results in somewhat higher efficienmcludmg ease of lgnmon bummg time com cies and aerosol yields tion temperature and pressure were recorded. Addr- Agents for dissemination which can be incorporated uonany the aerosol yleld into the formulation include for example organic dyes 4O such as methylaminoanthraquinone (MAAQ) used for W (Aerosol y'eld Total Wei ht Com osmon the production of colored smoke, the condensation g p product of chlorobenzaldehyde and malononitrile commonly employed as a tear gas and hereinafter desigand Efficiency, nated as CS, incapacitating agents which are psychotomimetics such as the classified materials having unclas- Agent in Aerosol Form X 100 sified U.S. Government code designations BZ and EA- (Effimncy Agent in Composition 3443, herbicides, fungicides, pesticides and the like.

By effective quantities of such agents is meant also were measured those amoun ts wh,ereby predetlarmmed level of treat The results of these studies are summarized in Tables fi f f reahzedh by one I and II. To aid in the ease of understanding and ready 5 l e m t e a o pyrotec lsselnmanon' presentation of the results, the operable and optimum h formulanons F be fabncated mto Compacts or composition ranges are shown in Table I. Table [1 sumgrams 9 techniques and procedures marizes the burning characteristics and compatibility gnployed m f f z g fi 55 characteristics exhibited by the compositions of corree componen s, p acmg e resu mg su s an 1a y Spending number in Table I.

Table l Fuel KClO Oxidizer Agent Comp. Component Parts by Weight Parts by Weight Component Parts by Weight Remarks Operable Preferred Operable Preferred Operable Preferred min. max. min. max. min. max. min. max. min. max. min. max.

la TSC l0 l7 23 29 MAAQ lb TSC l0 l2 28 29 MAAO" 60 System not completely optimized 2 TCH l2 l9 21 28 MAAO" 6O Sysem not optim- 3a EBS 7 l7 25 36 MAAQ 50 60 3b EBS 9 l2 28 30 MAAQ 60 System not Completely optimized 4a EBS 6 l8 2O 33 CS 56 Table l-continued Fuel KClO Oxidizer Agent Comp. Component Parts by Weight Parts by Weight Component Parts by Weight Remarks No. Operable Preferred Operable Preferred Operable Preferred min. max. min. max. min. max. min. max. min. max. min. max.

4b EBS 8 12 23 25 CS 64 68 System not completely optimized 5a DTB 10 23 26 33 MAAQ 50 60 5b DTB 10 13 27 30 MAAQ 60 System not com pletely optimized "'Methylaminoanthraquinone having blended therewith 15 percent by weight dextrin 'Methylaminoanthraquinone Table II Burning Combustion Aerosol Effi- Time Temperature Combustion Ignition Yield ciency Compatibility Comp. Range range Pressure Charac- Range Range Surveil- No. (sec.) C.) Range teristics Impact Spark Friction lance General la l2l8 390 G G GtoM GtoM G G G G G lb l2-16 390 G G -38 59-63 G G G G G 2 10-22 350-510 LtoG G MtoG M toG G G G G G 3a 7-12 380-500 P to G P to G 28-42 56-69 G G G G G 3b 7-9 425-450 G G 38-42 63-69 G G G G G 4a 6-32 350-540 M to G G 26-54 43-82 G G G G G 4b 8-10 350-475 G G 48-54 71-82 G G G G G 5a 7-13 350-390 G G 27-37 50-62 G G G G G 5b 9-11 375-390 G G 36-37 -62 G G G G G P=Poor, L=Low M=Medium, G=Good (Based on Poor as minimum acceptable performance for use in agent dissemination "Formulation compatibility after long term (9-12 weeks) storage at about C.

EXAMPLE 2 KClO and CS or BZ agent. These were tested for resistance to impact, spark, friction and given a surveillance test as described for Example 1. In all of these studies, these were rated as Good. The general compatibility exhibited by each of these formulations also was Good.

EXAMPLE 4 Following the procedure set forth in Example 1, dithiobiurea, potassium chlorate and CS agent, with and without potassium chromate catalyst, were fabricated into end burning pyrotechnic disseminating grains. These were ignited and the combustion characteristics measured.

Table III Formulation Combustion Characteristics Fuel KClO Agent Burning Combustion Aerosol Efficiency Run Time Temperature Yield No. type type (sec.) C. REMARKS 1 E55 10.3 29.7 MAAQ 60.0 7 470 41 68 2 EBS 12.0 23.0 CS 65.0 10-11 445 46.5-53.5 72-82 3 TSC 12.0 28.0 MAAQ" 60.0 10.5 430 37.5 63

4 TCH 14.7 25.3 MAAQ" 60.0 12 500 not sampled not sampled Qualitative evaluation as determined visually indicated good aerosol yield and efficiency 5 DTB 12.8 27.2 MAAQ 60.0 9 380 37 61.5

6 E88 19.0 31.0 BZ 60.0 20 not recorded not sampled not sampled Grain was cool burning and qualitatively shown to burn with good aerosol yield and efficiency 05% by weight dextrin blended with MAAQ Additionally, the grains were tested for compatibility by evaluating their resistance to impact, spark, friction, surveillance. Their general compatibility also was EXAMPLE 3 Following the procedure set forth in Example 1, a

number of pyrotechnic disseminating formulations, 55 noted. Each composition rated as Good in all of the within the composition ranges set forth herein, were fabricated from thiosemicarbazide, thiocarbohydrazide, ethylenebis(thiosemicarbazide) and dithiobiurea,

compatibility tests.

Table IV presents the formulation compositions and combustion characteristics.

Table IV Formulation Combustion Characteristics DTB CS K CrO Burning Combustion Aerosol Fuel KClO Agent Catalyst Time Temperature Yield Efficiency Run No. (see) C.)

l l 1.5 28.5 60 19 380-400 41.5 69.2 2 ll.O 28.0 60 1 12.5 380 49.5 82.5 3 W5 27.5 60 2 12 300-340 5|.0 85.0

In a manner similar to that described for the foregoing experiments, pyrotechnic disseminating formulations having herbicides, fungicides, and the like pesticides incorporated therein can be prepared using the fuel and oxidizer system disclosed herein. It is to be understood that combustion catalysts, e.g. potassium chromate, copper chloride, platinum, rhodium, iridium, sodium dichromate, chromic acid (CrO copper chromite, ferric oxide and the like, as disclosed herein alternatively can be utilized in these compositions.

Various modifications can be made in the present invention without departing from the spirit or scope thereof for it is understood that 1 limit myself only as defined in the appended claims.

I claim:

1. A pyrotechnic disseminating formulation comprising a. from about 6 to about 23 weight per cent of an aminosubstituted thiourea as fuel,

b. from about to about 36 weight per cent of a member selected from the group consisting of alkali metal and ammonium chlorates and perchlorates as oxidizer, and

0. balance an agent to be disseminated selected from the group consisting of smoke producing organic dyes, tear gas, herbicides, fungicides, pesticides, and psychotomimetic incapacitating agents.

2. The composition as defined in claim 1 wherein the fuel is a member selected from the group consisting of thiosemicarbazide, ethylenebis (thiosemicarbazide), thiocarbohydrazide and dithiobiurea and the oxidizer is potassium chlorate.

3. The composition as defined in claim 2 wherein the fuel ranges from about 8 to about 13 weight per cent and the oxidizer ranges from about 23 to about 30 weight per cent.

4. The composition as defined in claim 1 and including up to about 10 weight per cent of a combustion catalyst.

5. The composition as defined in claim 1 and including from about 0.2 to about 2 weight per cent of a combustion catalyst.

6. The composition as defined in claim 5 wherein the combustion catalyst is potassium chromate. 

1. A PYROTECHNIC DISSEMINTING FORMULATION COMPRISING A. FROM ABOUT 6 TO ABOUT 23 WEIGHT PER CENT OF AN AMINOSUBSTITUTED THIOUREA AS FUEL, B. FROM ABOUT 20 TO ABOUT 36 WEIGHT PER CENT OF A MEMBER SELECTED FROM THE GROUP CONSISTIG OF ALKALI METAL AND AMMONIUM CHLORATES AND PERCHLORATES AS OXIDIZER, AND C. BALANCE AN AGENT TO BE DISSEMINATED SELECTED FROM THE GROUP CONSISTING OF SMOKE PRODUCING ORGANIC DYES, TEAR GAS, HERBICIDES, FUNGICIDES, PESTICIDES, AND PSYCHOTOMIMETIC INCAPACITATING AGENTS.
 2. The composition as defined in claim 1 wherein the fuel is a member selected from the group consisting of thiosemicarbazide, ethylenebis (thiosemicarbazide), thiocarbohydrazide and dithiobiurea and the oxidizer is potassium chlorate.
 3. The composition as defined in claim 2 wherein the fuel ranges from about 8 to about 13 weight per cent and the oxidizer ranges from about 23 to about 30 weight per cent.
 4. The composition as defined in claim 1 and including up to about 10 weight per cent of a combustion catalyst.
 5. The composition as defined in claim 1 and including from about 0.2 to about 2 weight per cent of a combustion catalyst.
 6. The composition as defined in claim 5 wherein the combustion catalyst is potassium chromate. 